Improvement on the official documentation

[ced (Cédric Krier)]

@udono

My vision is to have one category for each functionality named in the functional documentation overview.

I do not think creating more categories is good for the forum.
Indeed there are tags already used for that.

@udono

WDYT?

I think we have already a place for every topic in the documentation. We are just missing the volunteers to make the edition.